This invention concerns preservation of freshly cut fruit, both from a microbiological aspect and from the aspect of flavor balance. In particular, the invention is directed at the preservation of flavor and shelf life in freshly cut pineapple.
Fresh fruits have enjoyed increasing popularity in recent times, primarily because of the need for a balanced diet, the health benefits and low calories in fruits, and superior flavor of fresh fruit as compared to canned fruit. In addition, interest in tropical and more exotic fruits has increased.
Fresh pineapple fruit is widely popular, but there are some inconveniences in consumption of pineapple for the average consumer. Whole pineapple is too large for a single serving, is difficult to prepare and involves considerable waste. Approximately 55% to 65% of a whole pineapple can be inedible, including the crown, depending on size of the pineapple.
Like many other ready-to-eat (non-canned) fruits, pineapple fruit as it has currently been offered has several deficiencies. The quality of the fruit is inconsistent due to seasonal variations and growing conditions, discoloration, juice and texture loss. Frequent spoilage of fruit occurs even prior to expiration of a relatively short shelf life. The short shelf life, typically a maximum of about 14 days, causes problems of limited distribution and high cost of air transport rather than surface transport, and occasions high costs due to return of spoiled fruit.
Prior to this invention no effective process has existed for preserving the flavor and balance of fresh fruit, particularly pineapple, while enhancing the shelf life of the fruit considerably beyond 14 days, to the extent that the fruit has a very fresh and acid-balanced flavor upon consumption.
The following U.S. patents have some relevance to various aspects of the process described below: U.S. Pat. Nos. 127,944, 1,305,244, 2,210,133, 2,308,486, 3,120,441, 3,398,001, 4,001,435, 4,021,585, 4,547,381, 4,883,674, 4,895,729, 5,244,684, 5,277,922, 5,279,843, 5,468,508, 5,614,238, 5,616,354, and 6,007,863.
In accordance with one form of the present invention, a method for maintaining the freshness of freshly cut pineapple fruit includes collecting juice from harvested pineapples, in separate juice batches during a pineapple growing year, the batches varying in Brix/acid ratio, and pasteurizing the juice. On harvesting pineapples, the pineapples are cut and the Brix and acid of the pineapple are determined to thus determine the Brix/acid ratio for the pineapple.
The process then involves selecting juice from at least one previously stored pineapple juice batch, to produce a juice with Brix/acid ratio which will balance the Brix/acid ratio of the newly harvested pineapple, the object being that the pineapple and juice when combined will have a combined Brix/acid ratio in a preselected range. The pineapple juice preferably has been filtered and chilled, freezing as necessary, for storage prior to its selection.
The freshly cut pineapple is treated to reduce surface microflora, and this step can be, for example, dipping in a chlorine solution. In a preferred embodiment the cut pineapple fruit is chilled to 28xc2x0 (just above freezing) to 45xc2x0 F. The chilled cut pineapple is then packaged with the selected juice or juice blend, and the pineapple/juice combination is stored in a chilled state, which in one preferred embodiment is just above freezing, e.g. about 28xc2x0 to 30xc2x0 F.
The preselected range of combined Brix/acid ratio for the pineapple fruit and juice preferably is about 19, or more generally, in the range of about 16 to 23.
The invention also applies to other fruits in general, the principle being that the freshly cut fruit is immersed in juice which will balance its Brix/acid ratio to a preselected range. Moreover, the juice can be a liquid medium other than juice of the same fruit: juice from a different fruit or blend of different fruits, sweet or tart syrups or other liquid media selected to balance the Brix/acid ratio of the freshly cut fruit as desired. The fruit and juice are not subjected to heat after packaging.
In one particular application, fresh pineapple is immersed and stored in white grape juice. The white grape juice is selected to balance the Brix/acid ratio of the pineapple to a preselected range to allow for optimal flavor and increase the life of the product. White grape juice has been found in many cases even better than pineapple juice in enhancing shelf life and maintaining flavor of fresh pineapple. Though grape juice is used in the industry, typically as a sweetener, or to extend juice in juice blends, or as a medium for fruit cocktails, the use of grape juice to preserve fresh pineapples has not been known and its benefits were not apparent. Grape juice has been used previously as a medium for canned fruit or other shelf stable products. This invention is concerned, however, with fresh, refrigerated produce, a wholly different application achieving a very beneficial and flavorful result.
It is thus a broad object of this invention to preserve the freshness and enhance the acid balance of freshly cut fruit by immersing the cut fruit in juice, syrup or liquid having Brix/acid ratio which will balance that of the fruit, the immersion preserving the fruit and enhancing shelf life as well as preserving and enhancing flavor. A more specific object is to preserve the freshness and shelf life of pineapple in this way, preferably using a balancing medium, preferably white grape juice. These and other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment, considered along with the accompanying drawings.